Ask Mr. Smarty Plants

Now, I see that you have answered your own plant identification question.   I suppose your plant was either Trillium erectum (Red trillium) or, perhaps, Trillium sessile (Toadshade).  You would not have found it by doing the search I suggested in your first question because the database refers to the color of the flowers for the two trilliums as "red" and not "purple".   The information about T. erectum on eFloras, however, says that the flowers can be "red, maroon or dark purple."   The general information about the Genus Trillium on eFloras tells us that what we are calling "leaves" aren't true leaves, but bracts.  A bract, according to our Glossary of Botanical Terms, is:

"A reduced or modified leaf occurring at the base of a flower or group of flowers. Bracts are sometimes arranged in rows, like shingles on a roof, usually closely cupping the blossoms of Compositae (Sunflower Family); see also Phyllaries. Sometimes brightly colored or petallike, as in Castilleja (paintbrush), or threadlike, as in Daucus carota (Queen Anne's lace)."

Nowhere in the eFloras description of trilliums did I see any mention that sometimes one of the bracts is missing or reduced.  The missing or reduced third leaf (bract) would make identification difficult.  I am, however, very happy you figured out what your plant is.

I believe that this is the other question about trilliums from Rochester, NY that you referred to.